There are many applications, particularly in mining and in industry, in which continuous conveyor belts are utilized to move bulk materials such as coal, grain, and the like from one location to another. In any system of this kind, the bulk material must be deposited on the moving conveyor belt; interruption of belt movement to receive a new load is economically infeasible. At the discharge end, it is usually necessary to scrape or clean the belt to make sure that all of the bulk material is left at the desired new location. Both ends of such a continuous belt conveyor system presents substantial problems; this invention is concerned with the problems and difficulties that occur in depositing bulk material on the moving belt for transport to a distant location.
A major problem of the input station of any continuous conveyor belt system is leakage of the bulk material being transported by the system. Broadly speaking, this has been met to a substantial extent by resilient aprons affixed to rigid skirtboards around the input station. Examples previously known resilient skirtboard aprons and apron mounts are disclosed in Gordon U.S. Pat. Nos. 4,231,471, 4,436,446, 4,877,125, and 4,989,727. Perhaps the best such skirtboard apron is the simple but effective device described and claimed in Gordon U.S. Pat. No. 4,989,727 and sold commercially under the designation ATLASTASEAL. Even that skirtboard apron, however, may have leakage problems, particularly as the result of appreciable movement of the conveyor belt, vertically or laterally, other than in the conveying direction through the input station.
It has been conventional, in the input stations for continuous belt conveyor systems, to support the conveyor belt in a generally open upwardly-facing U-shaped configuration at the input station, usually on three separate series of idler or support rollers. This input station configuration has one set of horizontally oriented support rollers extending longitudinally of the center of the belt. On each side there is another set of support rollers projecting upwardly at an acute angle and supporting a side portion of the belt.
Inevitably, there is some sagging of the belt between each set of support rollers. This leads to leakage problems at the input station. In part, this kind of leakage has been reduced by modifying the input station of the conveyor belt system to afford a plurality of elongated stationary support plates or rails under the conveyor belt. As with the rollers, the side portions of the belt are supported at an acute angle to the center portion, which is basically horizontal. However, the benefit of the resulting reduction in leakage, while desirable, is at least in part offset by increased drag on the conveyor belt, which may produce appreciable wear on the belt and which also may increase the costs of operation for the conveyor.